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Repairing Leaks

What causes leaks in water systems?

Leaks in water systems can result from external frost damage, dry solder joints, accidental perforation during maintenance or decoration, or internal corrosion.

What should be done?

Sealing internal leaks (central heating systems only)
Small leaks, including pressure drops on combination boilers and other sealed systems, can be repaired using Fernox Leak Sealer F4. Each Leak Sealer F4 treats 100 litres, 26 US gallons of circulating water or up to 10 single radiators.

On an open vented system draw off 5-10 litres of water from the drain cock initially and return this to the header tank to ensure that no treated water is thrown away. Repeat the previous step until all Leak Sealer has been absorbed into the circulating system.

On a sealed system pour Leak Sealer F4 500ml into a towel rail.
Switch on the circulating pump and apply at least a small amount of heat to achieve even distribution.

An alternative solution is to inject Fernox Superconcentrate Leak Sealer F4 directly into the radiator.

Repairing external leaks (to all types of water pipes)
To repair leaking external pipes and fittings, use Fernox LS-X External Leak Sealer with a bandage of Fernox PTFE plumber’s tape or another suitable reinforcement such as Fernox Leak-Fix tape or Fernox Fix-It putty.

After turning off the water and draining down to remove water pressure from the leak, apply Fernox LS-X to a dry surface all round the area of leakage. Wrap the pipe with a layer of PTFE tape or other reinforcement with 50% overlap and extend well beyond the area of the leak.

Immediately apply repeat coats of LS-X and further layers of bandage to form a repair about 5mm in total thickness. Then allow to cure.